999640026812 has 24 divisors (see below), whose sum is σ = 2045774941056. Its totient is φ = 418453964208.

The previous prime is 999640026811. The next prime is 999640026817. The reversal of 999640026812 is 218620046999.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999640026811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 415131698 + ... + 415134105.

It is an arithmetic number, because the mean of its divisors is an integer number (85240622544).

Almost surely, 2^999640026812 is an apocalyptic number.

It is an amenable number.

999640026812 is an abundant number, since it is smaller than the sum of its proper divisors (1046134914244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999640026812 is a wasteful number, since it uses less digits than its factorization.

999640026812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 830265857 (or 830265855 counting only the distinct ones).

The product of its (nonzero) digits is 3359232, while the sum is 56.

The spelling of 999640026812 in words is "nine hundred ninety-nine billion, six hundred forty million, twenty-six thousand, eight hundred twelve".